Protocol Independent Multicast Sparse Mode (PIM-SM) (see, IETF RFC4601 of August 2006) is a well known and commonly adopted protocol for constructing and maintaining multicast trees in Internet Protocol (IP) multicast communication networks. In order to distribute multicast content to recipient nodes (hereinafter also referred to as “destinations”) of the multicast communication network, PIM-SM uses a single multicast tree. A single multicast tree lacks redundancy for re-routing multicast traffic in case of a network failure.
PIM-SM is commonly used nowadays for constructing multicast paths for real-time traffic (e.g., for Internet Protocol TV (IPTV)). However, because PIM-SM strongly depends on unicast routing, in case of a network failure multicast recovery needs to wait until unicast routing has recovered. Thus, failure reaction for PIM-SM is relatively slow and is, therefore, a serious drawback for real-time applications. In order to overcome this drawback, IETF RFC5714 of January 2010 proposes an Internet Protocol (IP) fast re-route mechanism the uses a secondary path for an incoming multicast stream of a network node, thereby providing an immediate alternative path should the network node lose its connection with its primary upstream neighbor node. However, the proposed approach does not provide an efficient failure detection technique and does not handle all of the possible failure scenarios. Moreover, the proposed approach is a “live-live” protection technique, which means that the “secondary” traffic is always present even in a failure free situation. This secondary traffic can cause significant extra load in a multicast network.